Digital Image Steganographer Identification:A Comprehensive Survey

The rapid development of the internet and digital media has provided convenience while also posing a potential risk of steganography abuse.Identifying steganographer is essential in tracing secret information origins and preventing illicit covert communication online.Accurately discerning a steganographer from many normal users is challenging due to various factors,such as the complexity in obtaining the steganography algorithm,extracting highly separability features,and modeling the cover data.After extensive exploration,several methods have been proposed for steganographer identification.This paper presents a survey of existing studies.Firstly,we provide a concise introduction to the research background and outline the issue of steganographer identification.Secondly,we present fundamental concepts and techniques that establish a general framework for identifying steganographers.Within this framework,state-of-the-art methods are summarized from five key aspects:data acquisition,feature extraction,feature optimization,identification paradigm,and performance evaluation.Furthermore,theoretical and experimental analyses examine the advantages and limitations of these existing methods.Finally,the survey highlights outstanding issues in image steganographer identification that deserve further research.

Covalently Bonded Ni Sites in Black Phosphorene with Electron Redistribution for Efficient Metal‑Lightweighted Water Electrolysis

The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers the high capability of black phosphorene(BP)with hydrogen and oxygen evolution reaction(HER/OER)bifunctionality.Through a facile in situ electro-exfoliation route,the ionized Ni sites are covalently functionalized in BP nanosheets with electron redistribution and controllable metal contents.It is found that the as-fabricated Ni-BP electrocatalysts can drive the water splitting with much enhanced HER and OER activities.In 1.0 M KOH electrolyte,the optimized 1.5 wt%Nifunctionalized BP nanosheets have readily achieved low overpotentials of 136 mV for HER and 230 mV for OER at 10 mA cm^(−2).Moreover,the covalently bonding between Ni and P has also strengthened the catalytic stability of the Ni-functionalized BP electrocatalyst,stably delivering the overall water splitting for 50 h at 20 mA cm^(−2).Theoretical calculations have revealed that Ni–P covalent binding can regulate the electronic structure and optimize the reaction energy barrier to improve the catalytic activity effectively.This work confirms that Ni-functionalized BP is a suitable candidate for electrocatalytic overall water splitting,and provides effective strategies for constructing metal-lightweighted economic electrocatalysts.

设计稳定的钌基析氢和析氧反应催化剂的基本原理

清洁和可再生能源具有地域性和间歇性,需要能量转换和存储技术来解决这些问题.氢气(H_(2))具有无毒、易得、经济、储量丰富和零碳排放的优势,作为能源媒介展现出巨大的潜力.而电分解水技术,因其高效性和便利性,成为了一种极具吸引力、应用前景广阔且可靠的能源技术.研究表明,在较宽的pH范围内,贵金属催化剂仍然是最优的析氢反应(HER)和析氧反应(OER)催化剂.其中,钌(Ru)作为一种相对便宜的铂族金属,显示出在HER中替代商业铂碳(Pt/C)催化剂以及在OER中替代铱(Ir)的潜力.然而,尽管在提高钌基催化剂的催化活性方面取得了很大进展,但其稳定性问题仍然是阻碍其实际应用的主要障碍.因此,迫切需要全面梳理和综述关于设计稳定钌基HER和OER催化剂的基本原理和最新进展,更好地理解钌基催化剂的催化机理,深入认识影响其稳定性的关键因素,以期为解决这一挑战提供有力的理论支持和实践指导.本文系统总结了钌基催化剂在电分解水反应中关于稳定性研究的最新进展.首先,简要介绍了钌基催化剂在HER/OER中的反应机理以及与之相关的理论计算、原位表征技术、稳定性测试手段和评价标准等方面的研究进展.接下来,详细探讨了钌基催化剂在HER/OER过程中的失活机制,包括载体腐蚀、奥斯特瓦尔德成熟、团聚、颗粒脱离、活性位点中毒、金属溶解、过度氧化和晶体结构坍塌等.基于以上对失活机制的认识,进一步归纳了提高钌基催化剂稳定性的设计策略和机制.在HER方面,从引入导电基底、构筑核壳结构、形成镶嵌结构、增强金属-载体相互作用、相转变工程以及调节中间体吸附和脱附行为等方面阐述了提高钌基催化剂稳定性的策略.对于OER过程,也总结了一系列提高钌基催化剂OER稳定性的策略,包括与铱杂化、构筑核壳结构、引入稳定的载体、化学掺杂、形成固溶体以及转变反应路径.在分析了各种策略的优缺点并提出改进方向后,还概述了钌基催化剂在全电解水以及器件中的研究现状.最后,指出了钌基催化剂稳定性研究所面临的挑战和未来的研究方向:(1)需要更贴近工业实际的稳定性测试策略和评价标准;(2)对失活机制的进一步研究;(3)原位技术的进一步发展和应用;(4)探索更多先进的改性策略,如非晶态载体、范德华异质结、自旋态调节以及微环境调节等;(5)关注实际应用中可能遇到的问题,如催化剂大规模制备、双功能催化剂的设计以及杂质的影响.综上,本文系统地总结了钌基催化剂的反应机制、稳定性测试方法与评价标准、失活机制、设计策略、研究进展、具体应用以及目前存在的挑战,希望能够进一步促进该领域深入水平研究.同时,本文对光催化、热催化、酶催化等催化领域的研究也提供一定的参考和借鉴.

DC-FIPD: Fraudulent IP Identification Method Based on Homology Detection

Currently,telecom fraud is expanding from the traditional telephone network to the Internet,and identifying fraudulent IPs is of great significance for reducing Internet telecom fraud and protecting consumer rights.However,existing telecom fraud identification methods based on blacklists,reputation,content and behavioral characteristics have good identification performance in the telephone network,but it is difficult to apply to the Internet where IP(Internet Protocol)addresses change dynamically.To address this issue,we propose a fraudulent IP identification method based on homology detection and DBSCAN(Density-Based Spatial Clustering of Applications with Noise)clustering(DC-FIPD).First,we analyze the aggregation of fraudulent IP geographies and the homology of IP addresses.Next,the collected fraudulent IPs are clustered geographically to obtain the regional distribution of fraudulent IPs.Then,we constructed the fraudulent IP feature set,used the genetic optimization algorithm to determine the weights of the fraudulent IP features,and designed the calculation method of the IP risk value to give the risk value threshold of the fraudulent IP.Finally,the risk value of the target IP is calculated and the IP is identified based on the risk value threshold.Experimental results on a real-world telecom fraud detection dataset show that the DC-FIPD method achieves an average identification accuracy of 86.64%for fraudulent IPs.Additionally,the method records a precision of 86.08%,a recall of 45.24%,and an F1-score of 59.31%,offering a comprehensive evaluation of its performance in fraud detection.These results highlight the DC-FIPD method’s effectiveness in addressing the challenges of fraudulent IP identification.

Preventive strategies for feeding intolerance among patients with severe traumatic brain injury:A cross-sectional survey

This study aimed to investigate the application status of preventive measures for feeding intolerance in patients with severe traumatic brain injury(STBI)in China and analysis the differences and their causes.Methods A cross-sectional survey was conducted.From December 2019 to January 2020,ICU nurses and physicians of 89 hospitals in China were surveyed by using a questionnaire on preventive strategies for feeding intolerance in patients with STBI.The questionnaire included two parts:the general information of participants(10 items)and application of preventive measures for feeding intolerance in STBI patients(18 items).Results Totally 996 nurses and physicians completed the questionnaire.Among various methods,gastrointestinal symptoms(85.0%)and injury severity(71.4%)were mostly used to assess gastrointestinal functions and risk of feeding intolerance among STBI patients,respectively.Initiating enteral nutrition(EN)within 24–48 h(61.5%),nasogastric tubes(91.2%),30°–45°of head-of-bed elevation(89.5%),continuous feeding by pump(72.9%),EN solution temperature of 38–40°C(65.5%),<500 ml initial volume of EN solution(50.0%),monitoring gastric residual volume with a syringe(93.7%),and assessing gastric residual volume every 4 h(51.5%)were mostly applied for EN delivery among STBI patients.Prokinetic agents(73.3%),enema(73.6%),probiotics(79.0%),antacid agents(84.1%),and non-nutritional preparations as initial EN formula(65.6%)were commonly used for preventing feeding intolerance among STBI patients.Conclusions The survey showed that nurses and clinicians in China have a positive attitude towards preventive strategies for feeding intolerance.However,some effective new technologies and methods have not been timely applied in clinical practice.We suggest that managers,researchers,clinicians,nurses,and other health professionals should collaborate to explore effective and standard preventive strategies for feeding intolerance among patients with STBI.

A model System for Validation of PET Radiopharmaceuticals: Focusing on Tumor Microenvironment

Positron emission tomography (PET) imaging has emerged as an important clinical tool for cancer management, and specifically targeted radiopharmaceuticals play critical roles on PET molecular imaging. Solid cancers have highly complex and heterogeneous microenvironment, this review focused on those microenvironmental factors such as hypoxia, proliferation and perfusion and, accordingly, a novel test system for validation of current and novel targeted imaging radiopharmaceuticals. In this review, we have introduced the establishment of cancer and metastases models in nude mice, visualization of microenvironmental components of hypoxia, proliferation, perfusion, stroma and necrosis in cancers and metastases for establishing the microenvironment based model system, and validation of several radio- pharmaceuticals such as 18F-fluoro-2-deoxyglucose (18F-FDG) 18F-fluorothymidine (18F-FLT), 18F-misonidazole (18F- FMISO) using the system. We found that 18F-FLT accumulates in proliferating cancer cells, while 18F-FMISO and 18F-FDG mostly accumulate in hypoxic and non-proliferative cancer cells, 18F-FDG shares roughly similar intratumoral distribution pattern with 18F-FMISO and IAZGP, but mutually excludes 18F-FLT. This model system validated current tracers for imaging glucose metabolism, hypoxia and proliferation in cancer and metastases, therefore, can be used for novel targeted radiopharmaceuticals validation.

Keggin型十二钨磷酸盐@g-C_(3)N_(4)皮克林乳液微反应器促进苯甲醛高效氧化

改进设计了一个12学时的综合化学实验。在现行教材Keggin型多酸合成与苯甲醛氧化反应基础上,引入双亲性二维材料g-C_(3)N_(4),构筑Keggin型多酸@皮克林乳液微反应器,通过实验改进促进了苯甲醛氧化反应的高效进行,实现了反应场所的优化设计。同时,Keggin型多酸的选择由十二钼磷酸(H_(3)PMo_(12)O_(40))改进为十二钨磷酸钾(K_(3)PW_(12)O_(40)),利用钨系多酸独特的抗氧化特性,促进催化反应的快速进行。K_(3)PW_(12)O_(40)的合成过程简单、原料绿色易得,避免了易燃溶剂(如乙醚)的使用。双亲性g-C_(3)N_(4)材料具有较大的比表面,亲水基团和共轭骨架结构可以同时吸附多酸分子、过氧化氢分子和苯甲醛分子,促进过氧化氢和苯甲醛的等摩尔比高效快速转化。相较于原教材内容,改进实验更加符合绿色化学“原子经济性”的特点,实验中红外光谱和薄层色谱表征技术的使用,加强了理论学习与实践操作的融合。该实验充分体现了成果导向(OBE)教育理念,以创新型人才培养为目标导向,将学科前沿研究成果引入本科生实验教学,培养化学类大学生的创新意识以及提升他们综合分析、解决问题的能力。

Atomic Cu Sites Engineering Enables Efficient CO_(2)Electroreduction to Methane with High CH_(4)/C_(2)H_(4)Ratio

Electrochemical reduction of CO_(2)into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO_(2)capture and utilization,resulting from their high catalytic activity and selectivity.The mobility and accessibility of active sites in Cubased catalysts significantly hinder the development of efficient Cu-based catalysts for CO_(2)electrochemical reduction reaction(CO_(2)RR).Herein,a facile and effective strategy is developed to engineer accessible and structural stable Cu sites by incorporating single atomic Cu into the nitrogen cavities of the host graphitic carbon nitride(g-C_(3)N_(4))as the active sites for CO_(2)-to-CH_(4)conversion in CO_(2)RR.By regulating the coordination and density of Cu sites in g-C_(3)N_(4),an optimal catalyst corresponding to a one Cu atom in one nitrogen cavity reaches the highest CH_(4)Faraday efficiency of 49.04%and produces the products with a high CH_(4)/C_(2)H_(4)ratio over 9.This work provides the first experimental study on g-C_(3)N_(4)-supported single Cu atom catalyst for efficient CH_(4)production from CO_(2)RR and suggests a principle in designing highly stable and selective high-efficiency Cu-based catalysts for CO_(2)RR by engineering Cu active sites in 2D materials with porous crystal structures.

MiR-148b-3p在肺腺癌中的表达及其与患者预后的相关性

背景与目的 MiR-148b-3p是一种重要的微小RNA,已经被报道与多种癌症密切相关,但其在肺腺癌中的作用仍不清楚。本研究的目的是检测miR-148b-3p在肺腺癌中的表达水平,并分析其与临床病理特征及患者预后的相关性。方法收集2011年1月-2012年12月在本科室经手术切除的肺腺癌患者的肿瘤标本123例,利用实时荧光定量PCR方法检测miR-148b-3p的表达量,分析其与患者临床病理特征的相关性。利用多因素Cox比例风险模型分析影响患者总生存的独立预测因子。利用Kaplan-Meier生存分析方法估计miR-148b-3p高表达组和低表达组患者的总生存期,并使用Log-rank检验方法进行显著性检验。结果在123例肺腺癌患者中,有71例高表达miR-148b-3p,52例低表达。miR-148b-3p与肿瘤的分化程度(P=0.001)、肿瘤大小(P=0.007)显著相关,而与年龄、性别、吸烟史、饮酒史、脉管癌栓、胸膜侵犯、淋巴结转移、远处转移和术后治疗不存在统计学显著的相关性。多因素Cox比例风险模型分析显示肿瘤大小(P=0.032)、淋巴结转移(P=0.005)和miR-148b-3p表达量(P=0.047)是影响患者总生存的独立预测因子。Kaplan-Meier生存分析显示miR-148b-3p高表达组患者的总生存显著优于miR-148b-3p低表达组患者(P=0.010)。结论 MiR-148b-3p在肺腺癌中与肿瘤的分化程度、肿瘤大小显著相关,并且是影响患者总生存的独立预测因子。MiR-148b-3p高表达组患者的总生存显著优于低表达组患者。因此,miR-148b-3p可能成为新的肺腺癌治疗靶标或预后生物标志物。

龙珠软膏促小鼠伤口愈合及抗菌作用

目的观察龙珠软膏对于伤口愈合的作用和抗菌作用。方法将40只昆明种小鼠随机分成4组:空白对照组、基质组(给予龙珠软膏基质)、生长因子凝胶组(给予重组表皮生长因子凝胶)、龙珠软膏组。小鼠麻醉后在背部剪出一直径约1.5 cm的圆形伤口,观察并记录伤口愈合情况。待伤口愈合后取愈合后的皮肤做胶原染色(masson染色)和苏木精-伊红染色(HE染色),观察局部新生血管与肉芽组织的形成、局部成纤维细胞与炎症细胞的数量、胶原纤维的增殖。分别检测龙珠软膏对金黄色葡萄球菌、大肠埃希菌、铜绿假单孢菌、耐甲氧西林金黄色葡萄球菌(MRSA)、耐青霉素金黄色葡萄球菌的最低抑菌浓度(MIC)。结果龙珠软膏可在伤口恢复早期促进痂块生成,亦能促进伤口恢复后期的痂块进一步形成,缩短伤口愈合时间。龙珠软膏对MRSA和耐青霉素的金黄色葡萄球菌MIC为0.23 mg·mL^(-1),对大肠埃希菌的MIC为0.94 mg·mL^(-1),对铜绿假单孢菌和金黄色葡萄球菌的MIC>1.25 mg·mL^(-1)。结论龙珠软膏对伤口的愈合具有促进作用,对MRSA和耐青霉素的金黄色葡萄球菌具有较好的抑制作用。

A Geometry-Based Non-Stationary MIMO Channel Model for Vehicular Communications

This paper derives a non-stationary multiple-input multiple-output(MIMO) from the one-ring scattering model. The proposed channel model characterizes vehicular radio propagation channels with considerations of moving base and mobile stations, which makes the angle of arrivals(AOAs) along with the angle of departures(AODs) time-variant. We introduce the methodology of including the time-variant impacts when characterizing non-stationary radio propagation channels through the geometrical channel modelling approach. We analyze the statistical properties of the proposed channel model including the local time-variant autocorrelation function(ACF) and the space cross-correlation functions(CCFs). We show that the model developed in this paper for non-stationary scenarios includes the existing one-ring wide-sense stationary channel model as its special case.

Experimental and Numerical Study on the Gas Explosion in Urban Regulator Station

Regulator station is an important part in the urban gas transmission and distribution system.Once gas explosion occurs,the real explosion process and consequences of methane gas explosion in the regulator station were not revealed systematically.In this study,a full-scale experiment was carried out to simulate the regulator station explosion process,and some numerical simulations with a commercial CFD software called FLACS were conducted to analyze the effect of ignition and vent conditions on the blast overpressure and flame propagation.The experimental results demonstrated that the peak overpressure increased as the distance from the vent increased within a certain distance.And the maximum overpressure appeared 3 m away from the door,which was about 36.6 kPa.It was found that the pressure-time rising curves obtained from the simulation are basically the same as the ones from the experiment,however,the time of reaching the peak pressure was much shorter.The numerical simulation results show that the peak overpressures show an increase trend as the ignition height decreased and the vent relief pressure increased.It indicates that the damage and peak overpressure of gas explosion could be well predicted by FLACS in different styles of regulator station.In addition,the results help us to understand the internal mechanism and development process of gas explosion better.It also offers technical support for the safety protection of the urban regulator station.

Porous NiCo_2O_4 nanowires supported on carbon cloth for flexible asymmetric supercapacitor with high energy density

Recently, binary metal oxides have been considerably researched for energy storage since it can provide higher electrical conductivity and electrochemical activity than single components. Besides, rational arrays structure design can effectively enhance the utilization of active material. In this article, we synthesis a porous NiCo_2O_4 nanowires arrays, which were intimate contact with flexible carbon cloth（CC）by a facile hydrothermal reaction and calcination treatment. The rational array structures of NiCo_2O_4 facilitate the diffusion of electrolyte and effectively increase the utilization of active material. The asobtained NiCo_2O_4@CC electrode exhibits a high capacitance of 1183 mF cm^（-2） and an outstanding capacitance retention of 90.4% after 3000 cycles. Furthermore, a flexible asymmetric supercapacitor（ASC）using NiCo_2O_4@CC as positive electrode and activated carbon cloth（ACC） as negative electrode was fabricated, which delivers a large capacitance of 750 mF cm^（-2）（12.5 F cm^（-3））, a high energy density of 0.24 mWh cm^（-2）（3.91 mWh cm^（-3））, as well as excellent cycle stability under different bending states.These remarkable results suggest that as-assembled NiCo_2O_4@CC//ACC ASC is a promising candidate in flexible energy storage applications.

从成人学习者认知发展特点看电大成人外语学习

成人教育,顾名思义为成人学习者而服务的教育,教育对象的不同规定了成人学习不能全盘复制儿童学习的研究成果。分析成人的认知特点,遵循成人学习者独特的认知发展规律进而因势利导,厘清成人学习者特殊的学习现状,以期帮助他们提高学习效率、掌握适合自己的学习方法、增进学习的满足感。

Research on Quality Assurance System of Talent Cultivation in Higher Vocational Colleges from the Background of Enrollment Expansion

The enrollment expansion of higher vocational education is not only a strategic measure to alleviate the structural contradiction of employment,but also an important support for economic transformation and upgrading.How to deal with the expansion of enrollment and ensure the quality of training is an important task of higher vocational colleges at this stage.Based on the development requirements of the new era,it is of great practical significance to build a perfect quality assurance system of talent training.

Fabrication of wide temperature lanthanum and cerium doped Cu/TNU-9 catalyst with excellent NH_(3)-SCR performance and outstanding SO_(2)+H_(2)O tolerance

The effects of La on the catalytic performance,SO_(2)and H2O resistance of Cu-Ce/TNU-9 catalyst were studied in the selective catalytic reduction of NO_(x)via ammonia(NH_(3)-SCR).The results show that the La doped Ce-Cu/TNU-9(CCL/T9)catalyst exhibits better SCR performance than Ce-Cu/TNU-9(CC/T9)and Cu/TNU-9(C/T9)in the wide temperature window(200-450℃)due to La benefiting from enhancing Cu^(+)+Ce^(4+)?Cu^(2+)-+Ce^(3+)to facilitate the electron transfer,which further accelerates the oxidation of NO into NO_(2)that leads to the"Fast SCR".The La can also enhance the surface acidic,redox property and is beneficial to the formation of oxygen vacancy.Meanwhile,the larger co ntent of Ce^(3+) can produce oxygen vacancy,resulting in rising SCR activity.The CCL/T9 has outstanding water and SO_(2) resistance,which may be due to the adso rbed S on the surface of these catalysts mainly existing in the form of a small amount of sulfate and sulfite,the decomposition of ammonium bisulphite under high temperature and the hydrophobicity of TNU-9 zeolite.

A CPK-Based Identity Authentication Scheme for IoT

As the power Internet of Things(IoT)enters the security construction stage,the massive use of perception layer devices urgently requires an identity authentication scheme that considers both security and practicality.The existing public key infrastructure(PKI)-based security authentication scheme is currently difficult to apply in many terminals in IoT.Its key distribution and management costs are high,which hinders the development of power IoT security construction.Combined Public Key(CPK)technology uses a small number of seeds to generate unlimited public keys.It is very suitable for identity authentication in the power Internet of Things.In this paper,we propose a novel identity authentication scheme for power IoT.The scheme combines the physical unclonable function(PUF)with improved CPK technology to achieve mutual identity authentication between power IoT terminals and servers.The proposed scheme does not require third-party authentication and improves the security of identity authentication for power IoT.Moreover,the scheme reduces the resource consumption of power IoT devices.The improved CPK algorithm solves the key collision problem,and the third party only needs to save the private key and the public key matrix.Experimental results show that the amount of storage resources occupied in our scheme is small.The proposed scheme is more suitable for the power IoT.

Green Development of Tourism in the Context of Ecological Civilization Construction in the New Era

Xi Jinping s thought on ecological civilization has pointed out the direction for the green development of tourism.In the context of ecological civilization construction in the new era,the development of tourism must take the road of green development,to achieve mutual promotion and common improvement of economic,social and ecological benefits,and help build a beautiful China.The green development of tourism has a strong leading and driving role.On the premise that its development cannot exceed the carrying capacity of ecological environment,economic benefits should be given consideration,and efforts should be made to constantly convert ecological and environmental resources into economic benefits,to take the road of overall development.The green development of tourism needs the joint participation of government,enterprises and tourists to achieve breakthroughs in tourism development strategy,tourism planning,tourism resources development,tourism management and other fields.

欧洲圣诞销期商家说OK

本刊德国专稿：2008年是全球经济动荡不安的一年，但欧洲人在圣诞节期间仍然舍得消费。在欧洲、特别是德国，绝大多数的玩具销售商对2008年圣诞节市场销情表示满意。